US20090085861A1

US20090085861A1 - Backlight driver and liquid crystal display including the same

Info

Publication number: US20090085861A1
Application number: US12/193,087
Authority: US
Inventors: Ki-Chan Lee; Dong-won Park; Hyun-Seok Ko
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Display Co Ltd
Priority date: 2007-09-28
Filing date: 2008-08-18
Publication date: 2009-04-02
Also published as: KR20090032711A; US20150035877A1; KR101394435B1; US9384701B2; CN101399027A; TWI441145B; US8902148B2; TW200915288A; EP2043080A1; JP5229718B2; JP2009086621A; CN101399027B

Abstract

A backlight driver and a liquid crystal display (LCD) including the same, in which the backlight driver includes an interface unit enabled in response to a first carry signal, receiving serially provided optical data, and outputting a second carry signal; and a plurality of control units controlling one or more light-emitting devices in response to the serially provided optical data.

Description

This application claims priority from Korean Patent Application No. 10-2007-0098164 filed on Sep. 28, 2007 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Technical Field
The present disclosure relates to a backlight driver and a liquid crystal display (LCD) including the same.
2. Discussion of Related Art
A conventional liquid crystal display (LCD) includes a first display substrate having a plurality of pixel electrodes, a second display substrate having a plurality of common electrodes, and a liquid crystal panel having a dielectrically anisotropic liquid crystal layer injected between the first and second display substrates. The LCD displays a desired image by forming an electric field between the pixel electrodes and the common electrodes that have a liquid crystal layer therebetween, adjusting the intensity of the electric field that aligns the liquid crystals, and thus controlling the amount of light being transmitted through the liquid crystal panel.
Because the LCD is not a self light-emitting display, it includes a plurality of light-emitting devices. As the number of light-emitting devices used in the LCD increases, the number of wires connected to the light-emitting devices is also increased.

SUMMARY OF THE INVENTION

Exemplary embodiments of the present invention provide a backlight driver that can reduce the number of wires utilized therein.
Exemplary embodiments of the present invention also provide a liquid crystal display (LCD) that can reduce the number of wires utilized therein.
The exemplary embodiments of the present invention are not restricted to the one set forth herein, however. The above and other exemplary embodiments of the present invention will become more apparent to one of ordinary skill in the art to which the present invention pertains by referencing the detailed description of the exemplary embodiments of the present invention given below.
According to an exemplary embodiment of the present invention, there is provided a backlight driver including an interface unit enabled in response to a first carry signal, receiving optical data serially provided, and outputting a second carry signal; and a plurality of control units controlling one or more light-emitting devices in response to the optical data.
According to an exemplary embodiment of the present invention, there is provided an LCD including a timing controller serially providing optical data; first through n-th backlight drivers enabled sequentially, receiving the optical data, and connected to each other in a cascade; a plurality of light-emitting devices connected to each of the first through n-th backlight drivers and emitting light in response to the optical data; and a liquid crystal panel receiving the light and displaying an image.
According to an exemplary embodiment of the present invention, there is provided an LCD including a timing controller; first through n-th backlight drivers serially interfacing with the timing controller; a plurality of light-emitting blocks corresponding to each of the first through n-th backlight drivers, each light-emitting block including one or more light-emitting devices; and a liquid crystal panel receiving light from the light-emitting blocks and displaying an image, wherein each of the first through n-th backlight drivers controls the luminances of the corresponding light-emitting blocks.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention will be understood in more detail from the following descriptions taken in conjunction with the attached drawings, in which:

FIG. 1 is a block diagram of a liquid crystal display (LCD) according to an exemplary embodiment of the present invention;

FIG. 2 is an equivalent circuit diagram of a pixel included in the LCD of FIG. 1;

FIG. 3 is a conceptual diagram useful for explaining the operations of first through n^thbacklight drivers illustrated in FIG. 1;

FIG. 4 is a block diagram of an i^thbacklight driver illustrated in FIG. 1;

FIG. 5 is a block diagram of an LCD according to an exemplary embodiment of the present invention;

FIG. 6 is a block diagram of an LCD including an i^thbacklight driver according to an exemplary embodiment of the present invention;

FIG. 7 is a conceptual diagram useful for explaining the operation of a serial-parallel converter illustrated in FIG. 6;

FIG. 8 is a block diagram of an LCD including first through n^thbacklight drivers according to an exemplary embodiment of the present invention;

FIGS. 9 through 10D are conceptual diagrams useful for explaining the operations of first through eightieth light-emitting blocks illustrated in FIG. 8;

FIG. 11 is a block diagram of an LCD including first through n^thbacklight drivers according to an exemplary embodiment of the present invention;

FIG. 12 is a block diagram of an i^thbacklight driver illustrated in FIG. 11

FIG. 13 is a block diagram of an LCD including first through n^thbacklight drivers according to an exemplary embodiment of the present invention;

FIG. 14 is a block diagram of an LCD including first through n^thbacklight drivers according to an exemplary embodiment of the present invention;

FIG. 15 is a block diagram of an LCD including first through n^thbacklight drivers according to an exemplary embodiment of the present invention; and

FIG. 16 is a block diagram of an i^thbacklight driver illustrated in FIG. 15.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Exemplary embodiments of the present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. The invention may, however, be embodied in many different forms and should not be construed as being limited to the exemplary embodiments set forth herein; rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those of ordinary skill in the art. Like reference numerals in the drawings denote like elements, and thus their duplicate description will be omitted.
Hereinafter, a backlight driver and a liquid crystal display (LCD) including the same according to an exemplary embodiment of the present invention will be described with reference to FIGS. 1 through 4. FIG. 1 is a block diagram of an LCD 10 according to an exemplary embodiment of the present invention. FIG. 2 is an equivalent circuit diagram of a pixel PX included in the LCD 10 of FIG. 1. FIG. 3 is a conceptual diagram for explaining the operations of first through n^thbacklight drivers 900_1 through 900 _— n illustrated in FIG. 1. FIG. 4 is a block diagram of an i^thbacklight driver 900 _— i illustrated in FIG. 1.
Referring to FIG. 1, the LCD 10 includes a liquid crystal panel 300, a gate driver 400, a data driver 500, a timing controller 800, the first through n^thbacklight drivers 900_1 through 900 _— n, and a plurality of light-emitting devices L1 through Ln connected to the first through n^thbacklight drivers 900_1 through 900 _— n, respectively. The timing controller 800 may functionally be divided into a first timing controller 600 and a second timing controller 700. The first timing controller 600 may control an image displayed on the liquid crystal panel 300, and the second timing controller 700 may control the first through n^thbacklight drivers 900_1 through 900 ₁₃ n. The first timing controller 600 and the second timing controller 700 need not be physically separated from each other as shown in FIG. 1.
An equivalent circuit of the liquid crystal panel 300 includes a plurality of display signal lines and a plurality of pixels (not shown) connected to the display signal lines, respectively. The signal lines include a plurality of gate lines G1 through Gk and a plurality of data lines D1 through Dj.
As described above, the liquid crystal panel 300 includes a plurality of pixels, and an equivalent circuit of one of the pixels included in the liquid crystal panel 300 is illustrated in FIG. 2. Referring to FIG. 2, a pixel PX connected to, for example, an f^th(f=1˜i) gate line Gf and a g^th(g=1˜j) data line Dg includes a switching device Qp connected to the f^thgate line Gf and the g^thdata line Dg and a liquid crystal capacitor Clc and a storage capacitor Cst connected to the switching device Qp. The liquid crystal capacitor Clc includes a pixel electrode PE of a first display substrate 100 and a common electrode CE of a second display substrate 200. In addition, a color filter CF is formed on a portion of the common electrode CE.
The data driver 500 of FIG. 1 receives a data control signal CONT1 from the first timing controller 600 and applies an image data voltage to the data lines D1 through Dj. The data control signal CONT1 includes image signals corresponding to red (R), green (G) and blue (B) signals R, G, and B and signals for controlling the operation of the data driver 500. The signals for controlling the operation of the data driver 500 may include a horizontal start signal for initiating the operation of the data driver 500 and an output command signal for instructing the output of the image data voltage.
The gate driver 400 receives a gate control signal CONT2 from the first timing controller 600 and transmits a gate signal to the gate lines G1 through Gk. The gate signal includes a gate-on voltage Von and a gate-off voltage Voff provided by a gate-on/off voltage generator (not shown). The gate control signal CONT2 is used to control the operation of the gate driver 400 and may include a vertical start signal for initiating the operation of the gate driver 400, a gate clock signal for determining an output time of the gate-on voltage Von, and an output enable signal for determining a pulse width of the gate-on voltage Von.
The gate driver 400 or the data driver 500 may be mounted directly on the liquid crystal panel 300 in the form of a plurality of driving integrated circuit chips. Alternatively, the gate driver 400 or the data driver 500 may be mounted on a flexible printed circuit film (not shown) and then attached to the liquid crystal panel 300 in the form of a tape carrier package. Alternatively, the gate driver 400 or the data driver 500 may be integrated into the liquid crystal panel 300, together with the display signal lines, that is, the gate lines G1 through Gk and the data lines D1 through Dj, and the switching device Qp.
The first timing controller 600 receives the R, G, and B signals and a plurality of control signals for controlling the display of the R, G, and B signals from an external graphic controller (not shown). Then, the first timing controller 600 generates the data control signal CONT1 and the gate control signal CONT2 based on the R, G, and B signals and the control signals. The control signals include a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a main clock Mclk, and a data enable signal DE. The first timing controller 600 transmits a backlight control signal CONT3 to the second timing controller 700. The backlight control signal CONT3 may include optical data. The optical data is used to control the luminance of each of the light-emitting devices L1 through Ln.
The second timing controller 700 receives the backlight control signal CONT3 from the first timing controller 600 and serially provides the optical data to the first through n^thbacklight drivers 900_1 through 900 _— n. In this exemplary embodiment, the optical data may be provided through a serial bus SB. In addition, the second timing controller 700 transmits a start signal LS to the first backlight driver 900_1.
The first through n^thbacklight drivers 900_1 through 900 _— n are connected to each other in cascade and, thus, are sequentially enabled. In addition, the first through n^thbacklight drivers 900_1 through 900 _— n receive the serially provided optical data. Referring to FIGS. 1 and 3, the second timing controller 700 serially transmits optical data LDAT1 through LDATi and, at the same time, transmits the start signal LS in a high level. Accordingly, the first backlight driver 900_1 is enabled in response to the start signal LS in the high level and receives the serially provided optical data LDAT1. In this exemplary embodiment, the second through n^thbacklight drivers 900_2 through 900 _— n do not receive the optical data LDAT1. After receiving the optical data LDAT1 corresponding to the first backlight driver 900_1, the first backlight driver 900_1 outputs a first carry signal CA_1 in a high level. At this time, the start signal LS may transit to a low level. If the start signal LS transits to a low level, the first backlight driver 900_1 does not receive the optical data LDAT2 through LDATi. Next, the second backlight driver 900_2 is enabled in response to the first carry signal CA_1 in the high level, receives the optical data LDAT2 corresponding to the second backlight driver 900_2, and outputs a second carry signal CA_2 in a high level. The i^thbacklight driver 900 _— i is enabled in response to a (i−1)^thcarry signal CA_i-1 in a high level, receives the optical data LDATi corresponding to the i^thbacklight driver 900_i, and outputs an i^thcarry signal CA_i in a high level.
The first through n^thbacklight drivers 900_1 through 900 _— n control the luminances of the light-emitting devices L1 through Ln in response to the optical data LDAT1 through LDATi, respectively. The first through n^thbacklight drivers 900_1 through 900 _— n will now be described in more detail using the i^thbacklight driver 900 _— i as an example and with reference to FIGS. 3 and 4. In this exemplary embodiment, a case where a boost converter provides a power supply voltage required to drive the light-emitting devices L1 through Ln will be described as an example. The present invention, however, is not limited thereto.
Referring to FIG. 4, the i^thbacklight driver 900 _— i includes an interface unit 910 _— i and a control unit that may include a pulse width modulation (PWM) generator 920 _— i and a switching device Q_D.
The interface unit 910 _— i that is enabled in response to the (i−1)^thcarry signal CA_i-1, receives the optical data LDATi corresponding to the i^thbacklight driver 900 _— i, and outputs the i^thcarry signal CA_i. For example, the interface unit 910 _— i is enabled in response to the (i−1)^thcarry signal CA_i-1 in a high level and is disabled after outputting the i^thcarry signal CA_i in a high level.
As described above, the control unit includes the PWM generator 920 _— i and the switching device Q_D. The control unit controls the luminance of the light-emitting device Li in response to the optical data LDATi corresponding to the i^thbacklight driver 900 _— i.
The PWM generator 920 _— i outputs a PWM signal PWM_i whose duty ratio is adjusted in response to the optical data LDATi. The switching device Q_Dis turned on or off in response to the PWM signal PWM_i, thereby connecting or disconnecting the light-emitting device Li to/from a ground node. For example, the switching device Q_Dis turned on in a section in which the PWM signal PWM_i is in a high level and connects the light-emitting device Li to the ground node. In this exemplary embodiment, a current IL flows through the light-emitting device Li, and thus the light-emitting device Li emits light. In addition, the switching device Q_Dis turned off in a section in which the PWM signal PWM_i is in a low level and disconnects the light-emitting device Li from the ground node. In this exemplary embodiment, the current I_Ldoes not flow through the light-emitting device Li, and thus the light-emitting device Li is turned off. A period of time during which the light-emitting device Li is turned on is determined by the section in which the PWM signal PWM_i is in a high level and the section in which the PWM signal PWM_i is in a low level. If the period of time during which the light-emitting device Li is turned on increases, the luminance of the light-emitting device Li is increased. In summary, the duty ratio of the PWM signal PWM_i is adjusted according to the optical data LDATi, and the luminance of the light-emitting device Li is adjusted according to the duty ratio of the PWM signal PWM_i. The control unit may control the luminance of the light-emitting device Li by adjusting the amount of current that flows through the light-emitting device Li, as well as by turning on or off the light-emitting device Li as described above.
The boost converter includes an inductor L, a diode D, a capacitor C, a switching device Q_B, and a clock generator 930 _— i. The boost converter boosts an input voltage Vin in response to a clock signal CK and provides a power supply voltage required to operate the light-emitting device Li. The clock generator 930 _— i may be implemented within the i^thbacklight driver 900 _— i. The boost converter is a well-known boosting circuit, and thus a detailed description thereof will be omitted for the sake of simplicity.
In the first through n^thbacklight drivers 900_1 through 900 _— n and the LCD 10 including the same, the timing controller 800 serially transmits the optical data LDAT1 through LDATi to the first through n^thbacklight drivers 900_1 through 900 _— n through the serial bus SB. Therefore, the number of wires between the timing controller 800 and the first through n^thbacklight drivers 900_1 through 900 _— n can be reduced. If the number of wires is reduced, manufacturing costs can be reduced, and problems caused by short circuits and disconnections of wires can be reduced.
Hereinafter, an LCD according to an exemplary embodiment of the present invention will be described with reference to FIG. 5. FIG. 5 is a block diagram of an LCD 11 according to an exemplary embodiment of the present invention. Elements having the same functions as those illustrated in FIG. 1 are indicated by like reference numerals, and thus their description will be omitted.
Referring to FIG. 5, unlike what is described in relation to the initially described exemplary embodiment, in the present exemplary embodiment, a first timing controller 601 of the LCD 11 transmits a start signal LS to a first backlight driver 900_1. In this case, the start signal LS may be one of a data control signal CONT1 and a gate control signal CONT2. For example, the start signal LS may be any one of a vertical start signal for initiating the operation of the gate driver 400 of FIG. 1, a gate clock signal for determining an output time of a gate-on voltage Von, an output enable signal for determining a pulse width of the gate-on voltage Von, a horizontal start signal for initiating the operation of the data driver 500 as shown in FIG. 1 and an output command signal for instructing the output of an image data voltage. Alternatively, the start signal LS may be a signal synchronized with any one of the above-described signals or may be a combination of these signals. Alternatively, the start signal LS may be any one of a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a main clock Mclk and a data enable signal DE, may be a signal synchronized with any one of the same, or may be a combination of the same.
A backlight driver and an LCD including the same according to an exemplary embodiment of the present invention will now be described with reference to FIGS. 6 and 7. FIG. 6 is a block diagram of an LCD including an i^thbacklight driver 901 _— i according to an exemplary embodiment of the present invention. FIG. 7 is a conceptual diagram for explaining the operation of a serial-parallel converter 941 _— i illustrated in FIG. 6. Elements having the same functions as those illustrated in FIG. 4 are indicated by like reference numerals, and thus their description will be omitted.
Referring to FIG. 6, unlike what is described in relation to the previous exemplary embodiment, in the present exemplary embodiment, each backlight driver, for example, the i^thbacklight driver 901 _— i, controls a plurality of, for example, eight light-emitting devices Li_1 through Li_8. In order to control the light-emitting devices Li_1 through Li_8, the i^thbacklight driver 901 _— i includes the serial-parallel converter 941 _— i and a plurality of control units. The control units include a plurality of PWM generators 921 _— i through 928 _— i and a plurality of switching devices Q_D _— ₁through Q_D _— ₈, respectively.
More specifically, referring to FIGS. 6 and 7, an interface unit 911 _— i is enabled in response to a (i−1)^thcarry signal CA_i-1 and receives optical data LDATi that is serially provided. Then, the interface unit 911 _— i outputs an i^thcarry signal CA_i. The serial-parallel converter 941 _— i converts the serially input optical data LDATi into parallel optical data. For example, if the i^thbacklight driver 900 _— i controls the eight light-emitting devices Li_1 through Li_8 individually, the optical data LDATi corresponding to the i^thbacklight driver 900 _— i includes eight pieces of sub optical data LDATi_1 through LDATi_8. The serial-parallel converter 941 _— i provides the sub optical data LDATi_1 through LDATi_8 in parallel to the PWM generators 921 _— i through 928 _— i, respectively.
As described above, the control units include the PWM generators 921 _— i through 928 _— i and the respective switching devices Q_D _— ₁through Q_D _— ₈and control the respective luminances of the light-emitting devices Li_1 through Li_8, respectively, in response to the parallel optical data.
A backlight driver and an LCD including the same according to an exemplary embodiment of the present invention will now be described with reference to FIGS. 8 through 10D. FIG. 8 is a block diagram of an LCD 12 including first through n^thbacklight drivers 902_1 through 902 _— n according to an exemplary embodiment of the present invention. FIGS. 9 through 10D are conceptual diagrams for explaining the operations of first through eightieth light-emitting blocks LB_1 through LB_80 illustrated in FIG. 8. Elements having the same functions as those illustrated in FIG. 1 are indicated by like reference numerals, and thus their description will be omitted.
Referring to FIG. 8, the LCD 12 includes a timing controller 802, the first through n^thbacklight drivers 902_1 through 902 _— n, and a plurality of, for example, the first through eightieth, light-emitting blocks LB_1 through LB_80. Each of the first through eightieth light-emitting blocks LB_1 through LB_80 includes at least one light-emitting device.
The timing controller 802 serially interfaces with each of the first through n^thbacklight drivers 902_1 through 902 _— n. In this case, the timing controller 802 may serially interface with each of the first through n^thbacklight drivers 902_1 through 902 _— n using a serial bus SB.
If the timing controller 802 serially provides optical data to the first through n^thbacklight drivers 902_1 through 902 _— n through the serial bus SB, each of the first through n^thbacklight drivers 902_1 through 902 _— n may be enabled in response to a carry signal and receive its corresponding optical data as described above. Alternatively, if each of the first through n^thbacklight drivers 902_1 through 902 _— n has a unique address, the timing controller 802 may serially provide an address signal and optical data corresponding to each of the first through n^thbacklight drivers 902_1 through 902 _— n to each of the first through n^thbacklight drivers 902_1 through 902 _— n through the serial bus SB. Then, each of the first through n^thbacklight drivers 902_1 through 902 _— n may be enabled in response to the address signal and can receive the optical data. In this case, the timing controller 802 can use various methods other than the above methods in order to provide the optical data to each of the first through n^thbacklight drivers 902_1 through 902 _— n through the serial bus SB.
Eight of the first through eightieth light-emitting blocks LB_1 through LB_80 correspond to each of the first through n^thbacklight drivers 902_1 through 902 _— n. For example, the first through eighth light-emitting blocks LB_1 through LB_8 correspond to the first backlight driver 900_1, and the ninth through sixteenth light-emitting blocks LB_9 through LB_16 correspond to the second backlight driver 900_2. That is, the first backlight driver 900_1 controls the first through eighth light-emitting blocks LB_1 through LB_80, and the second backlight driver 900_2 controls the ninth through sixteenth light-emitting blocks LB_9 through LB_16. The first through eightieth light-emitting blocks LB_1 through LB_80 may be arranged in a matrix. For example, the first through eightieth light-emitting blocks LB_1 through LB_80 may be arranged in a matrix with eight rows and ten columns (n=10). The first through eightieth light-emitting blocks LB_1 through LB_80 may be implemented in a region 301 facing the liquid crystal panel 300 illustrated in FIG. 1 and emit light to the liquid crystal panel 300.
Each of the first through n^thbacklight drivers 902_1 through 902 _— n controls the luminances of eight corresponding ones of the first through eightieth light-emitting blocks LB_1 through LB_80. More specifically, referring to FIGS. 8 and 9, the first backlight driver as shown at 900_1 in FIG. 1 may reduce the luminances of the first and second light-emitting blocks LB_1 and LB_2 in first and second rows 1st ROW and 2nd ROW of a first column of an 8×10 matrix shown in FIG. 9 and increase the luminances of the third through eighth light-emitting blocks LB_3 through LB_8 in third through eighth rows 3rd ROW through 8th ROW in the first column. The second backlight driver 900_2 may reduce the luminances of the ninth and tenth light-emitting blocks LB_9 and LB_10 in the first and second rows 1st ROW and 2nd ROW of a second column of the 8×10 matrix and increase the luminances of the eleventh through sixteenth light-emitting blocks LB_11 through LB_16 in the third through eighth rows 3rd ROW through 8th ROW in the second column. The third through n^thbacklight drivers 902_3 through 902 _— n may increase the luminances of the seventeenth through eightieth light-emitting blocks LB_1 through LB_80 in the first through eighth rows 1st ROW through 8th ROW of third through tenth columns, respectively. That is, each of the first through n^thbacklight drivers 902_1 through 902 _— n can control the luminances of eight corresponding ones of the first through eightieth light-emitting blocks LB_1 through LB_80 according to an image displayed on a liquid crystal panel 300. If the luminance of each of the first through eightieth light-emitting blocks LB_1 through LB_80 is controlled according to an image displayed on the liquid crystal panel 300, power consumption can be reduced.
Alternatively, the first through n^thbacklight drivers 902_1 through 902 _— n may control the first through eightieth light-emitting blocks LB_1 through LB_80 to be turned on or off in units of rows. More specifically, referring to FIGS. 8 and 10A through 10D, at a time t1, light-emitting blocks in the first through third rows 1st ROW through 3rd ROW of the 8×10 matrix may be turned on, and those in the fourth through eighth rows 4th ROW through 8th ROW may be turned off. At a time t2, light-emitting blocks in the second through fourth rows 2nd ROW through 4th ROW may be turned on, and those in the first row 1st ROW and the fifth through eighth rows 5th ROW through 8th ROW may be turned off. At a time t3, light-emitting blocks in the third through fifth rows 3rd ROW through 5th ROW may be turned on, and those in the first row 1st ROW, the second row 2nd ROW and the sixth through eighth rows 6th ROW through 8th ROW may be turned off. At a time t4, light-emitting blocks in the fourth through sixth rows 4th ROW through 6th ROW may be turned on, and those in the first through third rows 1st ROW through 3rd ROW, the seventh row 7th ROW and the eighth row 8th ROW may be turned off. In this way, the first through eightieth light-emitting blocks LB_1 through LB_80 may be sequentially turned or off in units of rows. If each of the first through eightieth light-emitting blocks LB_1 through LB_80 is turned off according to time, the effect of inserting a black image between images displayed on the liquid crystal panel 300 may be produced. Therefore, when a moving image is displayed, superior display quality, like that which can be experienced in cathode ray tubes (CRTs), can be obtained.
Backlight drivers controlling the operations of light-emitting blocks and an LCD including the same will further be described below in each exemplary embodiment of the present invention.
A backlight driver and an LCD including the same according to an exemplary embodiment of the present invention will be described with reference to FIGS. 11 and 12. FIG. 11 is a block diagram of an LCD 13 including first through n^thbacklight drivers 903_1 through 903 _— n according to an exemplary embodiment of the present invention. FIG. 12 is a block diagram of an i^thbacklight driver 903 _— i illustrated in FIG. 11. Elements having the same functions as those illustrated in FIGS. 6 and 8 are indicated by like reference numerals, and thus their description will be omitted.
Referring to FIG. 11, unlike what is shown in the previously described exemplary embodiments, in the present exemplary embodiment, a second timing controller 703 of the LCD 13 transmits a load signal LOAD to the first through n^thbacklight drivers 903_1 through 903 _— n. The first through n^thbacklight drivers 903_1 through 903 _— n receive the load signal LOAD and control the luminances of first through eightieth light-emitting blocks LB_1 through LB_80 corresponding to the first through n^thbacklight drivers 903_1 through 903 _— n, respectively, in response to input optical data. By receiving the load signal LOAD, the first through n^thbacklight drivers 903_1 through 903 _— n can simultaneously control the luminances of the first through eightieth light-emitting blocks LB_1 through LB_80 in response to the optical data. Therefore, the first through n^thbacklight drivers 903_1 through 903 _— n can control the luminances of the first through eightieth light-emitting blocks LB_1 through LB_80 at each time t1, t2, t3 or t4 as illustrated in FIGS. 10A through 10D, respectively.
More specifically, referring to FIGS. 11 and 12, each of the first through n^thbacklight drivers 903_1 through 903 _— n includes an interface unit 911 _— i, a serial-parallel converter 941 _— i, a plurality of holding units 951 _— i through 958 _— i, a plurality of switching units SW1 _— i through SW8 _— i, and a plurality of control units. The control units include a plurality of PWM generators 921 _— i through 928 _— i and a plurality of switching devices Q_D ₁through Q_D _— ₈, respectively. For example, if the first through eightieth light-emitting blocks LB_1 through LB_80 are arranged in a 8×10 matrix, there may be ten first through n^thbacklight drivers 903_1 through 903 _— n, and there may be eight holding units 951 _— i through 958 _— i and light switching units SW1 _— i through SW8 _— i.
As described above, the serial-parallel converter 941 _— i converts optical data LDATi serially provided into parallel optical data. Then, each of the holding units 951 _— i through 958 _— i stores the parallel optical data. The switching units SW1 _— i through SW8 _— i transmit the parallel optical data to the control units, respectively, in response to the load signal LOAD. Accordingly, the control units control the luminances of the first through eightieth light-emitting blocks LB_1 through LB_80, respectively, in response to the parallel optical data.
Because each of the first through n^thbacklight drivers 903_1 through 903 _— n includes the holding units 951 _— i through 958 _— i, the switching units SW1 _— i through SW8 _— i and the control units, they can control the luminances of each of the first through eightieth light-emitting blocks LB_1 through LB_80, as illustrated in FIG. 9.
In addition, because the second timing controller 703 transmits the load signal LOAD to each of the first through n^thbacklight drivers 903_1 through 903 _— n, the luminances of the first through eightieth light-emitting blocks LB_1 through LB_80 can be controlled in units of rows at a specified time.
In the first through n^thbacklight drivers 903_1 through 903 _— n and the LCD 13 including the same according to the exemplary embodiment shown in FIG. 11, the luminances of the first through eightieth light-emitting blocks LB_1 through LB_80 can be controlled in units of blocks or in units of rows. Furthermore, because a timing controller 803 serially provides the optical data LDATi to the first through n^thbacklight drivers 903_1 through 903 _— n through the serial bus SB, the number of wires between the timing controller 803 and the first through n^thbacklight drivers 903_1 through 903 _— n can be reduced.
A backlight driver and an LCD including the same according to an exemplary embodiment of the present invention will be described with reference to FIG. 13. FIG. 13 is a block diagram of an LCD 14 including first through n^thbacklight drivers 904_1 through 904 _— n according to an exemplary embodiment of the present invention. Elements having the same functions as those illustrated in FIG. 11 are indicated by like reference numerals, and thus their description will be omitted.
Referring to FIG. 13, unlike what is shown in the previously described exemplary embodiments, in the present exemplary embodiment, a first timing controller 604 of the LCD 14 transmits a start signal LS and a load signal LOAD to the first through n^thbacklight drivers 904_1 through 904 _— n. In this case, the load signal LOAD may be one of a data control signal CONT1 and a gate control signal CONT2. For example, the start signal LS may be any one of a vertical start signal for initiating the operation of the gate driver 400 of FIG. 1, a gate clock signal for determining an output time of a gate-on voltage Von, an output enable signal for determining a pulse width of the gate-on voltage Von, a horizontal start signal for initiating the operation of the data driver 500 of FIG. 1 and an output command signal for instructing the output of an image data voltage. Alternatively, the load signal LOAD may be a signal synchronized with any one of the above signals or may be a combination of the above signals. Alternatively, the load signal LOAD may be any one of a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a main clock Mclk and a data enable signal DE, may be a signal synchronized with any one of the same, or may be a combination of the same.
A backlight driver and an LCD including the same according to an exemplary embodiment of the present invention will be described with reference to FIG. 14. FIG. 14 is a block diagram of an LCD 15 including first through n^thbacklight drivers 905_1 through 905 _— n according to an exemplary embodiment of the present invention. Elements having the same functions as those illustrated in FIG. 11 are indicated by like reference numerals, and thus their description will be omitted.
Referring to FIG. 14, unlike what is shown in the previously described exemplary embodiments, in the present exemplary embodiment, a load signal LOAD may be an n^thcarry signal CA_n of the n^thbacklight driver 905 _— n. More specifically, the first through n^thbacklight drivers 905_1 through 905 _— n are sequentially enabled and thus receive optical data. When the n^thbacklight driver 905 _— n is enabled and thus receives optical data, it outputs the n^thcarry signal CA_n. When the n^thcarry signal CA_n is provided to the first through n^thbacklight drivers 905_1 through 905 _— n as the load signal LOAD, the first through n^thbacklight drivers 905_1 through 905 _— n control the luminances of first through eightieth light-emitting blocks LB_1 through LB_80 in response to input optical data.
A backlight driver and an LCD including the same according to an exemplary embodiment of the present invention will be described with reference to FIGS. 15 and 16. FIG. 15 is a block diagram of an LCD 16 including first through n^thbacklight drivers 906_1 through 906 _— n according to an exemplary embodiment of the present invention. FIG. 16 is a block diagram of an i^thbacklight driver 906 _— i illustrated in FIG. 15. Elements having the same functions as those illustrated in FIG. 11 are indicated by like reference numerals, and thus their description will be omitted.
Referring to FIG. 15, unlike what is shown in the previously described exemplary embodiments, a timing controller 806 does not transmit a start signal LS to the first backlight driver 906_1. Instead, the timing controller 806 provide an address signal and optical data to the first backlight driver 906_1 through a serial bus SB. That is, the first through n^thbacklight drivers 906_1 through 906 _— n are not enabled in response to the start signal LS or first through (n-1)^thcarry signals CA_1 through CA_n-1, respectively. Instead, the first through n^thbacklight drivers 906_1 through 906 _— n are enabled in response to corresponding address signals and receive corresponding optical data. After providing optical data to each of the first through n^thbacklight drivers 906_1 through 906 _— n, the timing controller 806 can transmit the load signal LOAD to the first through n^thbacklight drivers 906_1 through 906 _— n at the same time. An address signal and optical data may be provided through a single serial bus or different serial buses. If the address signal and the optical data are provided through a single serial bus, the serial bus may be an inter-integrated circuit (I2C) bus.
Referring to FIG. 16, each backlight driver, for example, the i^thbacklight driver 906 _— i, serially interfaces with the timing controller 806 using an I2C interface method. That is, the serial bus SB includes a clock line SCL and a data line SDA, and an address signal and optical data corresponding to the i^thbacklight driver 906 _— i are provided to the i^thbacklight driver 906 _— i through the datra line SDA. In addition, the address signal and the optical data are synchronized with a clock signal of the clock line SCL and transmitted accordingly. Since the I2C interface method is a well-know serial interface method, a detailed description thereof will be omitted.
The i^thbacklight driver 906 _— i includes an interface unit 916 _— i interfacing with the timing controller 806 using the I2C interface method. That is, when receiving an address signal corresponding to the i^thbacklight driver 906 _— i, the interface unit 916 _— i receives optical data that is serially transmitted. In order to perceive the address signal corresponding to the i^thbacklight driver 906_i, the i^thbacklight driver 906 _— i may further include an address unit 960 _— i. That is, the address unit 960 _— i provides a unique address of the i^thbacklight driver 906 _— i to the interface unit 916 _— i. The interface unit 916 _— i receives the unique address of the i^thbacklight driver 906 _— i. In addition, when receiving the address signal corresponding to the i^thbacklight driver 906 _— i through the serial bus SB, the interface unit 916 _— i receives corresponding optical data.
The address unit 960 _— i may include a plurality of switching devices connected to a digital voltage Vdd. For example, the address unit 960 _— i may provide the unique 4-bit address of the i^thbacklight driver 906 _— i using four switching devices connected respectively to address pins PA through PA4 of the interface unit 916 _— i. The interface unit 960 _— i according to exemplary embodiments of the present invention, however, is not limited to the above example. That is, the address unit 960 _— i may also be a memory providing the unique address of the i^thbacklight driver 906 _— i.
As described above, in a backlight driver and an LCD including the same according to exemplary embodiments of the present invention, the number of wires connecting backlight drivers and a timing controller and the number of wires connecting the backlight drivers and light-emitting devices can be reduced. Accordingly, manufacturing costs of the LCD can be reduced. In addition, since problems caused by short circuits and disconnections of wires can be reduced, reliability of the LCD can be improved.
While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. The exemplary embodiments should be considered in a descriptive sense only and not for purposes of limitation.

Claims

1. A liquid crystal display (LCD) comprising:

a timing controller serially providing optical data;

first through n-th backlight drivers enabled sequentially, receiving the optical data, and connected to each other in cascade;

a plurality of light-emitting devices respectively connected to each of the first through n-th backlight drivers and emitting light in response to the optical data; and

a liquid crystal panel receiving the light and displaying an image.

2. The LCD of claim 1, further comprising a serial bus serially transmitting the optical data output from the timing controller, wherein each of the first through n-th backlight drivers is connected to the serial bus.

3. The LCD of claim 1, wherein the first backlight driver is enabled in response to a start signal transmitted from the timing controller, receives the optical data, and outputs a first carry signal to a second backlight driver.

4. The LCD of claim 3, wherein an i-th backlight driver (1<i<n) is enabled in response to an (i−1)-th carry signal transmitted from an (i−1)-th backlight driver, receives the optical data, and outputs an i-th carry signal to an (i+1)-th backlight driver.

5. The LCD of claim 1, wherein an i-th backlight driver (1<i<n) comprises:

an interface unit enabled in response to an (i−1)-th carry signal transmitted from the (i−1)-th backlight driver, receiving the optical data, and outputting the i-th carry signal;

a serial-parallel converter converting the optical data serially input thereto into parallel optical data; and

a plurality of control units controlling the light-emitting devices, respectively, in response to the parallel optical data.

6. The LCD of claim 5, wherein the i-th backlight driver further comprises:

a plurality of holding units receiving the parallel optical data from the serial-parallel converter and storing the parallel optical data; and

a plurality of switching units enabled in response to a load signal and transmitting the parallel optical data to the plurality of control units, respectively.

7. A backlight driver comprising:

an interface unit enabled in response to a first carry signal, receiving serially provided optical data, and outputting a second carry signal; and

a plurality of control units controlling one or more light-emitting devices in response to the optical data received by the interface unit.

8. The backlight driver of claim 7, further comprising a serial-parallel converter converting the serially provided optical data into parallel optical data, wherein the plurality of control units control the one or more light-emitting devices, respectively, in response to the parallel optical data.

9. The backlight driver of claim 8, further comprising:

10. The backlight driver of claim 7, wherein each of the plurality of control units outputs a pulse width modulation (PWM) signal having a duty ratio adjusted in response to the optical data and controls the luminance of a corresponding one of the light-emitting devices using the PWM signal.

11. A liquid crystal display (LCD) comprising:

a timing controller;

first through n-th backlight drivers serially interfacing with the timing controller;

a plurality of light-emitting blocks corresponding respectively to each of the first through n-th backlight drivers, each light-emitting block including one or more light-emitting devices; and

a liquid crystal panel receiving light from the plurality of light-emitting blocks and displaying an image,

wherein each of the first through n-th backlight drivers controls respective luminances of the corresponding light-emitting blocks.

12. The LCD of claim 11, further comprising a serial bus serially transmitting optical data output from the timing controller, wherein each of the first through n-th backlight drivers is connected to the serial bus.

13. The LCD of claim 11, wherein the first through n-th backlight drivers are connected to each other in cascade, are sequentially enabled, and receive the optical data.

14. The LCD of claim 13, wherein the first backlight driver is enabled in response to a start signal transmitted from the timing controller, receives the optical data, and outputs a first carry signal to a second backlight driver.

15. The LCD of claim 14, wherein an i-th backlight driver (1<i<n) is enabled in response to an (i−1)-th carry signal transmitted from an (i−1)-th backlight driver, receives the optical data, and outputs an i-th carry signal to an (i+1)-th backlight driver.

16. The LCD of claim 13, wherein an i-th backlight driver (1<i<n) comprises:

an interface unit enabled in response to an (i−1)-th carry signal transmitted from an (i−1)-th backlight driver, receiving the optical data, and outputting an i-th carry signal;

a serial-parallel converter converting the optical data serially input into parallel optical data; and

a plurality of control units controlling the plurality of light-emitting blocks in response to the parallel optical data.

17. The LCD of claim 16, wherein the i-th backlight driver further comprises:

18. The LCD of claim 11, wherein the timing controller serially provides address signals, and each of the first through n-th backlight drivers is enabled in response to a corresponding one of the address signals and receives the optical data when enabled.

19. The LCD of claim 18, further comprising an inter-integrated circuit (I2C) bus serially transmitting the optical data and the address signals.

20. The LCD of claim 18, wherein each of the first through n-th backlight drivers comprises:

an interface unit enabled in response to a corresponding one of the address signals and receiving the optical data;

a plurality of control units controlling the light-emitting devices in response to the parallel optical data.

21. The LCD of claim 20, wherein each of the first through n-th backlight drivers further comprises:

22. The LCD of claim 11, wherein the plurality of light-emitting blocks are arranged in a matrix, each of the first through n-th backlight drivers corresponds to a column of the matrix of light-emitting blocks, and the first through n-th backlight drivers control the light-emitting blocks to be turned on or off in units of rows.